相关论文: Clustering around radio galaxies at z~1.5
An analysis of the cluster environments around distant radio galaxies is presented, in particular the results from new NTT deep optical-IR imaging of the fields of radio sources at z ~ 1.6. A net overdensity of K-band galaxies is found,…
Galaxy clusters at high redshift present a superb opportunity to study galaxy evolution, with large galaxy samples at fixed distances. Several lines of evidence point towards large formation redshifts and passive evolution for cluster…
The environments of a complete subsample of 6 of the most powerful radio-loud AGN at redshifts z~1.6 are investigated, using deep RJK imaging to depths of R~26, J~22.4 and K~20.6. An excess of galaxy counts in the K-band is seen across…
High redshift radio galaxies are amongst the most massive galaxies in the early Universe and have properties expected from central galaxies in forming clusters. We are carrying out an observational programme on the VLT to find and study…
Radio galaxies are uniquely useful as probes of large-scale structure as their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage…
We report a discovery of proto-cluster candidates around high redshift radio galaxies at z~2.5 on the basis of clear statistical excess of colour-selected galaxies around them seen in the deep near-infrared imaging data obtained with CISCO…
We study the environments of 6 radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant…
I review the current status of an on-going investigation into the stellar and dynamical ages of the oldest known galaxies at redshifts greater than 1. The spectroscopic data, when compared with the predictions of a range of recent…
We present measurements of the clustering properties of galaxies in the field of redshift range $0.5 \lesssim z \lesssim 1.5$ Ultra Steep Spectrum (USS) radio sources selected from Sydney University Molonglo Sky Survey and NRAO VLA Sky…
We explore the environments of two radio galaxies at z~1.5, 7C1751+6809 and 7C1756+6520, using deep optical and near-infrared imaging. Our data cover 15'x15' fields around the radio galaxies. We develop and apply BzK color criteria to…
To properly understand the evolution of high-redshift galaxy clusters, both passive and star-forming galaxies have to be considered. Here we study the clustering environment of 21 radio galaxies and quasars at 1<z<2.5 from the third…
The clustering properties of clusters, galaxies and AGN as a function of redshift are briefly discussed. It appears that extremely red objects at z ~ 1, and objects with J-K > 1.7 and photometric redshifts 2 < z_phot < 4 are highly…
We conduct a statistical analysis of the radio source population in galaxy clusters as a function of redshift by matching radio sources from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) catalog with 618 optically-selected…
I discuss the properties of a population of candidate cluster galaxies recently identified in the fields of radio-loud quasars at z=1--2. The magnitude, spatial, and color distributions of the excess galaxies in these fields are consistent…
An analysis of the environments around a sample of 28 3CR radio galaxies with redshifts 0.6 < z < 1.8 is presented, based primarily upon K--band images down to K ~ 20 taken using the UK Infrared Telescope (UKIRT). A net overdensity of…
We present near-infrared observations of the environments around three radio-loud sources (MG1 J0442+0202, 3C 068.2, and MS 1426.9+1052) at redshifts z=1.10,1.57, and 1.83 (respectively), that are surrounded by near-infrared galaxy…
Using a combination of near-infrared and optical photometry, along with multi-object spectroscopy, we have confirmed the existence of a high-redshift cluster of galxies at z = 0.96. The cluster was found using a wide-angle tailed radio…
We have carried out multicolour imaging of a complete sample of radio-loud quasars at 0.6 < z < 1.1 and find groups or clusters of galaxies in the fields of at least 8 and possibly 13 of the 21 sources. There is no evidence for an evolution…
We report on the discovery of a z=1.58 mature cluster around the high-redshift radio galaxy 7C1753+6311, first identified in the Clusters Around Radio-Loud AGN survey. Two-thirds of the excess galaxies within the central 1Mpc lie on a red…
Although field galaxy studies have begun to probe the universe at z > 1, evidence for galaxy clusters at such redshifts has been sparse. New observations are accumulating rapidly, however, providing new data on the early evolution of…